Sterilization container with self-sealing closure

ABSTRACT

A sterilization container holds instruments during a sterilization process. It has en enclosure with an opening into the enclosure. A self-closing mechanism at the opening keeps the opening closed when not attached to a sterilant delivery source.

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 09/470,244 filed Dec. 22, 1999, the entire contents of whichare incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to sterilization containers, andmore particularly to sterilization containers that are suitable for usein multiple sterilization processes.

BACKGROUND OF THE INVENTION

[0003] Medical instruments that are being sterilized for reuse aretypically sterilized within some form of sterilization container. Suchcontainers typically comprise a box having one or more openings forallowing the passage of sterilizing media. The media are typicallygaseous and may comprise steam, hydrogen peroxide or ethylene dioxide toname but a few. Such containers are typically sealed in some fashion soas to allow the sterilizating media to enter the container but not toallow contaminating microorganisms to enter.

[0004] One type of container has multiple openings and is wrapped in amaterial such as central supply room (CSR) wrap which is permeable tothe sterilizating media yet impermeable to contaminating microorganisms.An alternative is to provide filtered ports into and out of thecontainer, the ports having a filter media transmissive to thesterilization media and impermeable to the contaminating microorganisms.Typically the container will have some features inside to hold theinstruments from moving around inside the container. For instance, asilicone mat with upwardly protruding fingers may be employed.Alternatively, various clips and attaching devices are known. Sometimesa portion of the container, on an insert for the container, is molded toaccommodate a particularly instrument to be sterilized.

[0005] Since the types of sterilization processes vary, it is desirableto have a container that can accommodate different sterilizationprocesses. One attempt to achieve such a “universal” container isdisclosed in U.S. Pat. No. 6,379,631 by Wu, incorporated herein byreference, wherein it was found that liquid crystal polymers areparticularly suited for use in each of steam, hydrogen peroxide,ethylene dioxide sterilization processes.

[0006] Beyond the types of sterilization media, there exists a need fora container that can be employed in different sterilization processes,not merely in a process in which the container is placed into a chamberand the sterilization media introduced into the chamber. For instance itwould be desirable to also be able to use the sterilization container ina process lacking a chamber and wherein a source of sterilization mediaconnects directly to the container with the sterilization media beingintroduced into the container but not into the environment surroundingthe container. Further, one may desire to employ the container in aprocess in which the sterilization media is placed into the containerwith the instruments and released into a gaseous form after thecontainer is closed. These processes are disclosed in U.S. Pat. Nos.6,193,931 and 5,785,934, each of which is incorporated herein byreference.

SUMMARY OF THE INVENTION

[0007] A sterilization container, according to the present invention,for sterilizing, transporting and storing one or more medicalinstruments, comprises an enclosure defining an interior space adaptedto house the one or more medical instruments. The enclosure is sealedagainst the ingress of contaminating microorganisms. An opening into theenclosure has associated therewith an adapter for attaching theenclosure to a source of sterilization vapor or mist, and the adapterhas a self-sealing closure.

[0008] Preferably, the adapter is selectively attachable to theenclosure.

[0009] The self-sealing closure can comprises a seat at the opening anda closing member engageable with the seat such that when the closingmember is engaged with the seat the closing member blocks fluidcommunication between the interior space and an environment exterior ofthe enclosure through the opening. Preferably, a biasing member urgesthe closing member toward the seat. In one aspect of the invention, theself-sealing closure has an inlet for receiving a projecting member froma source of sterilant, and the closing member is positioned with respectto the inlet such that when the projecting member is inserted into theinlet the projecting member abuts the closing member and moves it awayfrom the seat. In an alternative aspect of the invention, the closingmember has a first flange engageable by a second flange on theprojecting member whereby movement of the projecting member relative tothe inlet moves the closing member so that it can be opened or closed.

[0010] The self-sealing closure can comprise a semi-permeable filter atthe opening. Alternatively, the self-sealing closure can comprise ascreen at the opening.

[0011] Preferably, the sterilization container has one or more filteredports into the enclosure, each of which is preferably provided with acover for closing the port. An instrument holder can be provided withinthe enclosure.

[0012] A manually operated pressure release valve can be provided toallow the container to be stored at a pressure differing from ambientand thus allowing a user to check the integrity of the container seal bylistening for passage of air through the valve when it is opened.Preferably, the enclosure is formed of a liquid crystal polymer suitablefor use in steam, hydrogen peroxide and ethylene oxide sterilizationprocesses.

[0013] The sterilization container can have additional openings into theenclosure with their own self-sealing closure mechanisms.

[0014] In one aspect of the invention, a partition divides the enclosureinto a first portion and a second portion, the opening for attaching theenclosure to a source of sterilization vapor or mist being into thefirst portion, and an exit path out of the enclosure through the secondportion, wherein to flow the sterilization vapor or mist through theenclosure more efficiently. The exit path can comprise a separate exitport out of the container. Alternatively, the opening is divided into afirst path leading into the enclosure first portion and a second pathleading into the enclosure second portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a block diagram of a prior art sterilization containerin a sterilization chamber;

[0016]FIG. 2 is a block diagram of a self-sterilizing container;

[0017]FIG. 3 is a block diagram of a sterilization container accordingto the present invention connected to a sterilzer;

[0018]FIG. 4 is a front elevation view of an interface on the containerof FIG. 3, shown in an open position;

[0019]FIG. 5 is a front elevation view of the interface of FIG. 4 shownin a closed position;

[0020]FIG. 6 is a front elevation view of an alternative interface forthe container of FIG. 3;

[0021]FIG. 7 is a cut-away view of an insert for the interface of FIG. 6and having a self-closing mechanism shown in the closed position;

[0022]FIG. 8 is a cut-away view of the insert of FIG. 7, shown in theopen position;

[0023]FIG. 9 is a cut-away view of an alternative insert for theinterface of FIG. 6 and having a self-closing mechanism, shown in theclosed position;

[0024]FIG. 10 is a cut-away view of the insert of FIG. 9, shown in theopen position;

[0025]FIG. 11 is a cut-away view of an alternative embodiment of asterilization container according to the present invention; and

[0026]FIG. 12 is a cut-away view of a further alternative embodiment ofa sterilization container according to the present invention.

DETAILED DESCRIPTION

[0027]FIG. 1 discloses a prior art sterilization container 10 comprisingan enclosure 12 having a lid 14 and containing an instrument 16 to besterilized. Semipermeable filtered ports 18 allow sterilizating mediasuch as steam, hydrogen peroxide vapor or ethylene oxide to enter theenclosure 12 yet prevent ingress of contaminating microorganisms afterthe sterilization procedure is complete. The container 10 is enclosedwithin a sterilization chamber 20 that comprises a vacuum pump 22 fordrawing a vacuum on the chamber 20 and a cassette 24 loaded with chargesof liquid hydrogen peroxide that are vaporized by a vaporizer 26 andprovide vapor phase hydrogen peroxide to the chamber 20. More detail onvapor phase hydrogen peroxide sterilization can be found in U.S. Pat.Nos. 4,756,882, 4,817,800, 4,869,286, 4,899,519, 4,913,196 and4,941,518, each of which is incorporated herein by reference.

[0028] A biological indicator 28 and chemical indicator 30 are containedwithin a compartment 32, which is in fluid communication with theenclosure 12 through a semipermeable membrane 33, and which can beopened to remove the biological and chemical indicators 28 and 30 afterthe sterilization processes is complete without exposing the instrument16 to potentially contaminating microorganisms. A biological indicatorindicates whether a test microorganism has been successfully killed inthe sterilization process and a chemical indicator indicates thepresence of, and in some instances and integrated exposure to, thesterilization media. Examples of biological and chemical indicators canbe found in U.S. Pat. Nos. 5,552,320, 5,942,438, 6,218,189, and6,436,659 each of which is incorporated herein by reference.

[0029]FIG. 2 discloses a self-contained sterilization container 34comprising an enclosure 36 having a lid 38 and containing an instrument40 and a source of sterilant 42. At least one semipermeable port 44 ispreferably provided to allow excess sterilant to exit the enclosure 36yet prevent the ingress of contaminating microorganisms. A biologicalindicator 46 and chemical indicator 48 in a compartment 50, similar tothe container of FIG. 1, are also provided. The source of sterilant 42can be a solid complex that liberates a chemical sterilizing vapor, suchas the urea hydrogen peroxide complexes as disclosed in U.S. Pat. Nos.5,667,753, 5,674,450, 5,770,739 and 5,785,934, each of which isincorporated herein by reference, which liberates hydrogen peroxide whenheated. Alternatively, it can be a source of liquid sterilant, such as aliquid hydrogen peroxide solution, which is vaporized. Other chemicalvapor sterilants can be substituted therefore.

[0030] If the sterilant does take a liquid form it is preferablyseparated from the rest of the enclosure 36 by a vapor permeablemembrane 52. The membrane 52 can be a part of the enclosure, or theliquid sterilant can be contained in its own enclosure 54 having themembrane 52 as a part thereof and provided with a seal either over themembrane alone 52 or enclosing the entire enclosure 54 so that in usethe membrane can be unsealed and the enclosure 54 placed into thesterilization container 34 with the instrument 40. To release thesterilant, heat can be applied by heating the entire sterilizationcontainer 34, such as in an oven, or in a microwave oven. Alternativelyan electric heating element can be provided within the container 34 withits wires leading exterior of the enclosure 36. In one furtherembodiment, the enclosure 54 that contains the sterilant can be formedof a magnetic metal and an induction element, similar to an inductionelement on a kitchen cook-top can be used to heat the enclosure 54through the container 34 without unduly heating the container 34. Theone or more ports 44 can be sealed during a portion of this process tokeep the concentration of the sterilant within the enclosure 36relatively high to shorten the sterilization period and ensure a moreconsistent sterilization process.

[0031]FIG. 3 illustrates a third type of container 60 adapted to beconnected to a sterilizer 62. The container 60 comprises an enclosure 64having a lid 66 and containing an instrument 68. The enclosure 64 ispreferably formed of a material suitable for use in steam, hydrogenperoxide and ethylene oxide sterilization process, such as a liquidcrystal polymer as described in the aforementioned U.S. Pat. No.6,379,631. Suitable polymers include polybenzoate-naphthalate;polybenzoate-terphthalate-bisphenol-isophthalate;polybenzoate-terphthalate-ethylene glycol; and polynaphthalate-aminoterephthalate. The biological indicator 70 and chemical indicator 72 areprovided as in the previous two containers. The sterilizer 62 comprisesa vacuum pump 74 and a source of sterilant 76 which connect via aninterface 78 to the container 60.

[0032] The sterilizer 62 has a receiving bay 80 for receiving a portionof the container 60. An interface 82 on the container 60 interfaces withthe interface 78 on the sterilizer 62 to place the container enclosure64 into fluid communication with the vacuum pump 74 and sterilant source76. One or more valves 84 controls the fluid communication between thesterilant source 76 and the interface 78 and also the vacuum pump 74 andthe interface 78. A simple sterilization process would involve engagingthe container 60 into the receiving bay 80 of the sterilizer 62 and thendrawing a vacuum on the enclosure 64 via the vacuum pump 74. Once asufficient vacuum is established, sterilant from the sterilant source 76can be admitted into the enclosure 64 either in gaseous, mist, or liquidform and then the unvaporized portion thereof would quickly vaporize dueto the vacuum within the enclosure 64. A heated vaporizer (not shown)could be used to enhance the vaporization as the sterilant enters theenclosure 64. After a sufficient period of time the sterilant willeffect the sterilization of the instrument 68 and the container 60 canbe removed from the receiving bay 80.

[0033] The container 60 may either be left under vacuum or have itspressure normalized to atmospheric prior to removal of bay 80. If thevacuum is retained and a manually operated vacuum relief valve 86 isprovided, when the operator opens the vacuum relief valve 86 and hearsan inrush of air the operator will know that the integrity of thecontainer 60 has not been violated since the time of the sterilizationprocedure. More efficient sterilization cycles can also be employed inwhich the vacuum and sterilant admission steps.

[0034] Turning also to FIGS. 4 and 5, an interface 90 for the container60 allows the container 60 to operate effectively in the fashionsdepicted in FIG. 1, or FIG. 2, or FIG. 3. The interface 90 comprises anaperture 92 into the enclosure 64, the aperture 92 being covered by asemipermeable filter 94 to allow passage of sterilizing media yetdisallow passage of potentially contaminating microorganisms. An O-ringor gasket 96 surrounds the aperture 92 to help ensure a pressure tightseal with the interface 78 on the sterilizer 62. To close the aperture92 for use as depicted in the manner of FIG. 2, a panel 98 slides overthe aperture 92 and seals against the O-ring 96, as depicted in FIG. 5.

[0035] Turning also to FIG. 6, an alternative embodiment of an interface100 comprises an aperture 102 surrounded by an O-ring or gasket 104 andhaving a frame 106 to receive various inserts. A first insert 108 fitsinto the frame 106 and comprises a screen 110 having holes large enoughto easily pass a mist of sterilant media into the enclosure 64. A secondalternative insert 112 comprises a semipermeable filter 114 for passingvapor phase sterilant media yet disallowing passage of contaminatingmicroorganisms. A third insert 116 comprises merely a solid plate toblock the aperture 102 entirely.

[0036] The first insert 108 having the screen 110 would be most usefulfor use with a sterilizer such as the sterilizer 62 in which thesterilant media enters the container 60 as a mist and in which theinstruments 68 will not be stored in the container 60 after theprocedure but rather will be used immediately thereafter, or where suchinstruments do not require complete sterility after the procedure. Forinstance, if the instruments 68 are dental instruments, a high level ofsterilization efficiency may be desirable to kill difficult pathogensfrom a prior patient, but after the sterilization it would be acceptableto store the instruments in a clean environment yet not in a bacteriaproof enclosure.

[0037] The second insert 112 would be useful when the sterilizer 62admits vapor phase sterilant into the container 60, and would also beuseful in the sterilizer depicted in FIG. 1 where the container 60 wouldbe placed into a sterilization chamber 20.

[0038] The third insert 116 would primarily be useful when the containeris used as a self-contained sterilization container as in the mannerdepicted in FIG. 2.

[0039] Turning also to FIGS. 7 and 8, an alternative insert 120 fitsinto the frame 106 and is primarily useful when employing a mist form ofthe sterilization media in the sterilizer 62 combined with the need tostore the instruments 68 in the container 60 in a sterile form after thesterilization process is complete. The insert 120 employs a self-closingmechanism 121 which opens upon insertation of the container 60 into thesterilizer 62 to allow introduction of mist into the enclosure 64 andwhich closes automatically upon removal of the sterilization container60 from the sterilizer 62 to seal the enclosure 64 from potentiallycontaminating microorganisms. The insert 120 comprises a body 122 havinga flange 124 which fits into the frame 106 and seals against the O-ringor gasket 104. An open tube 126 extends outwardly from the body 122 toreceive an adapter 128 from the sterilizer interface 78. The body 122contains the self-closing mechanism 121. It comprises a valve member 130biased toward a valve seat 132 on the body by a spring 134 or otherbiasing member. When seated on the valve seat 132 the valve member 130seals the body 122 from the tube 126, thus effectively sealing thecontainer aperture 102.

[0040] The adapter 128 comprises a pipe 136 having a distal end 138 thatabuts the valve member 130 driving it away from the valve seat 132. Oneor more openings 140 of some form at or near the pipe distal end 138place the pipe 136 into fluid communication with the body 122 and thuswith the enclosure 64. Seals 142 provide a tight seal between the pipe136 and tube 126. Spring loaded members 144 engage detents 146 on thepipe 136 to hold it in place. Upon removal of the container 60 from thebay 80 the pipe 136 will disengage from the valve member 130 and closethe self-closing mechanism 121.

[0041] The mechanism of FIG. 7 relies upon the enclosure 64 to be nearor above ambient pressure to keep the self-closing mechanism 121 closed.With a pressure slightly above ambient, opening of the relief valve 84(FIG. 3) still causes an audible air rush to alert a user to theintegrity of the container's seal.

[0042] Turning to FIGS. 9 and 10, if a vacuum is desired for storage ofthe container 60, an alternative insert 150 may be used. It comprises abody 152 and flange 154 for connection to the container 60 and a tube156 for receiving an adapter 158 from the sterilizer 62 (not shown inFIGS. 9 and 10). The body 152 contains a valve member 160 biased towarda valve seat 162 by a biasing member 164. However, it differs from theprevious embodiment in that it closes toward the container 60, such thata vacuum in the container 60 holds the valve member 160 closed. A flange166 on the valve member 160 engages a flange 168 on a pipe 170 of theadapter 158. The pipe 170 rotates to engage the flanges 166 and 168 witheach other and is then retracted slightly to pull the valve member 160away from the valve seat 162. Seals 172 are provided between the pipe170 and tube 156. Spring loaded members 174 engage detents 176 on thepipe 170 to hold the parts in the proper orientation. After thesterilization process the process is reversed to seat the valve member160.

[0043] While the provision of various inserts 108, 112, 116, 120 and 150provides the most flexibility, either of the inserts 120 or 150 could beintegral with the container rather than removable to neverthelessprovide the container with the ability to be used interchangeably in theprocesses of FIG. 1 and FIG. 2 and FIG. 3.

[0044] Further, to enhance its flexibility, the container 60 may includemultiples of the features disclosed herein. For instance, especiallywhen configured with the inserts 120 and 150 with their self-closingfeature it is preferred to have, especially at the top and bottom of thecontainer 60 (best seen in FIG. 3), additional filtered ports 180 whichmay be sealed. Such ports could be similar to the interface 90, or couldhave screw-on covers or other sealing mechanisms. Preferably, thefilters can be replaced, as is preferable with any of the filtersdiscussed herein. Such additional ports provide enhanced diffusion ofsterilant into and out of the container 60 when used in a standardchamber 20 such as disclosed in FIG. 1. When used in the process of FIG.3 the ports 180 would be left closed.

[0045]FIG. 11 discloses an alternative embodiment of a container 200,especially useful in the sterilizer 62 of FIG. 3, but offering enhancedflow through the container 200. It comprises an enclosure 202 having alid 204, provision for a biological indicator 206 and chemical indicator208 and a sealable filtered port 210 in the lid 204. An inlet/exit port212 has an opening 214 for receiving a probe 216 from the sterilizer 60.A normally closed spring loaded valve 218 opens when the probe 216 isinserted into the opening 214 and abuts the valve 218. A solid partition220 separates the enclosure 202 into an upper portion 222 and lowerportion 224. A filtered aperture 226 in the partition, away from theport 212, connects the upper and lower portions 222 and 224. The opening214 is partitioned into an upper path 228 and lower path 230. A filteredpartition 232 separates the upper portion 222 from the upper path 228and the lower path 230 communicates with the lower portion 224. Theprobe 216 is preferably similarly separated into an upper path 234adapted to communicate with the opening upper path 228 and a lower path236 adapted to communicate with the port lower path 230.

[0046] When the probe 216 enters the opening 214 it opens the valve 218.Sterilizing media gases flow in from the probe upper path 234 into theopening upper path 228 and into the enclosure upper portion 222. Thesegases exit the enclosure 202 by flowing through the filtered aperture226 into the enclosure lower portion 224 and out through the opening andprobe lower paths 230 and 236. After the probe 216 is removed, thespring loaded valve 218 closes and seals the enclosure 202. Instrumentsfor sterilization, which were placed into the upper portion 222 throughthe lid 204, and are now sterile, are further protected fromcontamination by the filtered aperture 226 and filtered partition 232which will block ingress of potentially contaminating microorganismseven if the spring loaded valve 218 were to leak.

[0047]FIG. 12 illustrates a similar container 240 comprising anenclosure 242 having a lid 244, a filtered port 246 and provisions for abiological indicator 248 and chemical indicator 250. The enclosure 242is separated into an upper portion 252 and lower portion 254 by a solidpartition 256 having a filtered aperture 258. The container 240 has aninlet port 260 into the upper portion 252, with a spring-loaded valve262 and an exit port 264 from the lower portion 254, also with aspring-loaded valve 266. The inlet port 260 receives an inlet probe 268and the exit port 264 receives an exit probe 270. A filter 272 separatesthe inlet port 260 from the upper portion 252. Gases flow from the inletprobe 268 into the enclosure upper portion 252 and exit from the exitprobe 270 as in the previous embodiment. To allow for flow through ofmist based sterilants, such as a solution of hydrogen peroxide, thefilter 272 can be replaced by a screen and the aperture 258 need not befiltered. The valves 262 and 266 will protect the integrity of theenclosure 242 post sterilization.

[0048] The flow could be continuous, in which case it would bedesireable to continually recirculate the same sterilant through theenclosure 242. Alternatively, the exit probe 270 can be used to exhaustthe atmosphere in the enclosure 242 to a vacuum as low as 0.5 torr(depending upon the strength of the enclosure 242 and the vacuum pump)and then the inlet probe 268 can, especially in connection with a heatedvaporizer, supply sterilant such as hydrogen peroxide vapor to theenclosure 242. After a sufficient time to effect sterilization, the exitprobe 270 can draw out the sterilant.

[0049] One of skill in the art will recognize that the location of theports 260 and 264 can be changed to address other functional needs whilekeeping with the concept of flowing gases more efficiently through thecontainer 240. For instance, they could be located on the bottom of thecontainer with suitable partitioning within the enclosure 242 to routeincoming gases to the enclosure upper portion 252. Rather than havespring-loaded valve 262 and 266 which move directly away from theincoming probes 268 and 270, spring-loaded flap valves (not shown) whichrotate away from the incoming probe could be substituted therefor andwould not tend to push the probe out after its insertion.

[0050] While the invention has been particularly described in connectionwith specific embodiments thereof, it is to be understood that this isby way of illustration and not of limitation, and that the scope of theappended claims should be construed as broadly as the prior art willpermit.

What is claimed is:
 1. A sterilization container for sterilizing, transporting and storing one or more medical instruments, comprising: an enclosure defining an interior space adapted to house the one or more medical instruments, said enclosure sealed against the ingress of contaminating microorganisms; an opening into the enclosure having associated therewith an adapter for attaching the enclosure to a source of sterilization vapor or mist, the adapter comprising a self-sealing closure.
 2. A sterilization container according to claim 1 wherein the adapter is selectively attachable to the enclosure.
 3. A sterilization container according to claim 1 wherein the self sealing closure comprises a seat at the opening and a closing member engageable with the seat and wherein when the closing member is engaged with the seat the closing member blocks fluid communication between the interior space and an environment exterior of the enclosure through the opening.
 4. A sterilization container according to claim 3 wherein the self-sealing closure further comprises a biasing member urging the closing member toward the seat.
 5. A sterilization container according to claim 4 wherein the self-sealing closure comprises an inlet for receiving a projecting member from a source of sterilant, the closing member being positioned with respect to the inlet such that when the projecting member is inserted into the inlet the projecting member abuts the closing member and moves it away from the seat.
 6. A sterilization container according to claim 4 wherein the self-sealing closure comprises an inlet for receiving a projecting member from a source of sterilant, the closing member having thereon a first flange engageable by a second flange on the projecting member whereby movement of the projecting member relative to the inlet moves the closing member.
 7. A sterilization container according to claim 1 wherein the self-sealing closure comprises a semi-permeable filter at the opening.
 8. A sterilization container according to claim 1 wherein the self-sealing closure comprises a screen at the opening.
 9. A sterilization container according to claim 1 and further comprising one or more filtered ports into the enclosure.
 10. A sterilization container according to claim 9 wherein each of the one or more filtered ports comprise a cover for closing the port.
 11. A sterilization container kit according to claim 1 and further comprising an instrument holder within the enclosure.
 12. A sterilization container according to claim 1 and further comprising a pressure release valve.
 13. A sterilization container according to claim 1 wherein the enclosure is formed of a liquid crystal polymer.
 14. A sterilization container according to claim 1 wherein the self-sealing closure comprises a sealed inlet for receiving a projecting member from a source of sterilant.
 15. A sterilization container according to claim 1 having an additional opening into the enclosure with its own self-sealing closure mechanism.
 16. A sterilization container according to claim 1 and further comprising a partition dividing the enclosure into a first portion and a second portion, the opening for attaching the enclosure to a source of sterilization vapor or mist being into the first portion, and an exit path out of the enclosure through the second portion, wherein to flow the sterilization vapor or mist through the enclosure more efficiently.
 17. A sterilization container according to claim 16 wherein the exit path comprises a separate exit port out of the container.
 18. A sterilization container according to claim 16 wherein the opening is divided into a first path leading into the enclosure first portion and a second path leading into the enclosure second portion. 